title: Prevalence of ventricular arrhythmias in patients with cardiac resynchronization therapy without back-up ICD: a single-center experience.
abstract: OBJECTIVE
  Current guidelines recommend cardiac resynchronization therapy (CRT) in selected heart failure patients, but do not precisely clarify when a back-up implantable cardioverter defibrillator (ICD) should be associated (CRT-D). In this study we evaluate the occurrence of ventricular arrhythmias in a population of patients implanted with biventricular pacemaker without a back-up ICD (CRT-P).
  
  
  METHODS
  We performed a retrospective analysis on 84 patients (55 men, mean age 74 ± 7 years), implanted with a CRT-P since April 2000. Patients had in 31% an underlying coronary artery disease, in 56% an idiopatic dilated cardiomyopathy and in 13% a valvular disease. An upgrade to CRT-P was performed from previous conventional pacemakers in 36% of cases. Baseline New York Heart Association (NYHA) functional class was II in 25%, III in 63% and IV in 12%. Mean left ventricular ejection fraction was 29.8 ± 8.8% with two-dimensional echo. During follow-up, occurrence of ventricular arrhythmias was assessed clinically and through the pacemaker stored data at the scheduled check-up.
  
  
  RESULTS
  During a mean follow-up of 29 months (range 2-127 months), telemetry interrogation revealed unsustained ventricular tachyarrhythmias in 11 of 84 patients (13.1%). Only one patient experienced an episode of sustained ventricular tachycardia. An upgrading to a CRT-D was performed in two patients; one of these patients died suddenly 15 months after the upgrade. Death occurred in 20 of 84 patients (23.8%): 15 for refractory heart failure and five for noncardiac causes.
  
  
  CONCLUSIONS
  Our data show that CRT-P may be well tolerated in selected patients even during a long-term follow-up; and that an upgrade to CRT-D may not be enough to prevent sudden death.
authors.affiliation: aClinica Cardiologica, AOU Maggiore della Carità, Novara bStruttura di Cardiologia, Ospedale Santo Spirito, Casale Monferrato, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Bortnik
authors.forename: Anna
authors.initials: A
authors.lastname: Degiovanni
authors.forename: Gabriele
authors.initials: G
authors.lastname: Dell'era
authors.forename: Chiara
authors.initials: C
authors.lastname: Cavallino
authors.forename: Eraldo
authors.initials: E
authors.lastname: Occhetta
authors.forename: Paolo
authors.initials: P
authors.lastname: Marino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002423:Cause of Death; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000517:prevention & control*